1984 F150 4.9l 4 speed fuel economy
02-13-2017, 03:31 PM
#11
Junior Member
Just bought an 84 inline 6 2wd 4speed w/ overdrive and don't really know what mileage I'm getting as my fuel gauge has a mind of it's own. I noticed burnthelight mentioned these engines should get 12-15 mpg. I hope you mean city. I bought this truck partially because In my research it said these trucks can get 20 mpg highway. Mostly bought it for the price though. I know these are 30+ year old vehicles and you cant expect them to get the mileage they did when new but I really hope I'm not gonna be getting bad gas mileage with it.
02-27-2017, 07:28 PM
#12
Senior Member
Don't need a gas gauge to figure out mileage unless your vent tube causes the pump to shut off early. As long as the tank gets full and the pump shuts off automatically,...
Fill tank, don't top off or round up price. Write down mileage. Drive for a few days. Go back to gas station, fill tank. Look at new mileage. Divide total miles driven but number of gallons pumped into tank. That's your gas mileage.
As far as mileage, a brand new v6 wrangler, that's much smaller and weighs less (and is brand new), gets about 20-21MPG highway. If you wanted gas mileage, should've bought a civic. I've heard claims of guys getting 20 on the highway, I find it rather hard to believe. Gas mileage in 1984 just wasn't that much of a concern compared to today. The 300 will run forever though, will far outlive the body with basic upkeep.
Fill tank, don't top off or round up price. Write down mileage. Drive for a few days. Go back to gas station, fill tank. Look at new mileage. Divide total miles driven but number of gallons pumped into tank. That's your gas mileage.
As far as mileage, a brand new v6 wrangler, that's much smaller and weighs less (and is brand new), gets about 20-21MPG highway. If you wanted gas mileage, should've bought a civic. I've heard claims of guys getting 20 on the highway, I find it rather hard to believe. Gas mileage in 1984 just wasn't that much of a concern compared to today. The 300 will run forever though, will far outlive the body with basic upkeep.
02-28-2017, 07:21 AM
#13
Senior Member
These trucks have miles of vacuum lines. Mine was getting crappy mileage until i fixed the vacuum leaks and tuned the carb.
Remove the choke that's on the carb and install the manual one. It is an upgrade for sure. Then make sure the timing is correct and then adjust the idle screw on carb to get the maximum vacuum you can using a vacuum gauge. This should help immensely.
If you get really into it, you can do what I did and upgrade to a 3G alternator and then install electric fans. Helps the engine rev faster with out that heavy fan.
Next. Tires. What size do you have in the rear? I have the NP435 trans and 4th gear is 1:1. I have 31's and in town its 3rd gear all the way and anything over 40 MPH gets 4th and I get close to 20 on the highway at 75.
If you do not have to go through emissions you can register it as a classic and install an HEI distributor and a Holley 390 4 barrel carb or a 570 carb. Tune it old school and be done with it. As soon as my address changes to NC, I will be doing that swap..
Remove the choke that's on the carb and install the manual one. It is an upgrade for sure. Then make sure the timing is correct and then adjust the idle screw on carb to get the maximum vacuum you can using a vacuum gauge. This should help immensely.
If you get really into it, you can do what I did and upgrade to a 3G alternator and then install electric fans. Helps the engine rev faster with out that heavy fan.
Next. Tires. What size do you have in the rear? I have the NP435 trans and 4th gear is 1:1. I have 31's and in town its 3rd gear all the way and anything over 40 MPH gets 4th and I get close to 20 on the highway at 75.
If you do not have to go through emissions you can register it as a classic and install an HEI distributor and a Holley 390 4 barrel carb or a 570 carb. Tune it old school and be done with it. As soon as my address changes to NC, I will be doing that swap..